Unless you've been off the planet for the past few weeks, and cut off from all media from this one, you've heard about the remarkable, history making images that the New Horizons probe has been sending back of Pluto, but New Horizons has also been finding out some remarkable, history making things about one of Pluto's moons: Charon. The newest feature there NASA scientists have discovered is also the most puzzling. It's a huge mountain in the middle of a moat, or at least, that's what it looks like.
The first close-up image of Charon was released by NASA Thursday (July Jeff Moore, the leader of New Horizons' Geology, Geophysics and Imaging team says, "This is a feature that has geologists stunned and stumped."
The high resolution image that shows this feature on Charon was taken at about 6:30 a.m. EDT (10:30 UTC), just an hour and a half before New Horizons' closest approach to Pluto on July 14, 2015, from a range of only 49,000 miles (79,000 kilometers), using the probe's high resolution Long Range Reconnaissance Imager (LORRI). A much sharper view is in the way.
Why don't we have it yet? This vividly demonstrates just how far New Horizons has traveled from Earth: You're probably familiar with the concept of the speed of light. Though here on Earth we experience it as instantaneous because we're never that far away from anything, Charon is over three billion miles away from us. At those distances it takes light, and radio waves, which also travel at the speed of light, over four hours to reach us. Also the download speed is slower than an old dial-up modem. That's why New Horizons will be sending data back to NASA for quite some time to come. All told, it will take about 16 months for New Horizons to transmit all the data it collected as it flew through the Pluto system, that is Pluto and its five moons.
The image that contains the mountain in the moat is of a region of Charon that is approximately 240 miles (or 390 kilometers) from top to bottom. There are few craters visible in this image as well, "indicating a relatively young surface that has been reshaped by geologic activity," according to the New Horizons Geology, Geophysics and Imaging team. There's also a "swath of cliffs and troughs stretching about 600 miles (or 1,000 kilometers) [which] suggests widespread fracturing of Charon's crust, likely the result of internal geological processes." This is a surprise, as both Pluto and Charon were thought to be essentially dead ice balls floating in space.